The accurate firing of trajectory weapons requires that the range of the target be determined as accurately as possible, and that account should be taken of crosswind along the projectile trajectory. The first factor affects the required position of the weapon axis in the vertical plane, while the second affects its position in the horizontal plane. Since aiming weapons, particularly small-sized ones, requires aligning the weapon sight aiming point (such as crosshair, red dot etc.) with the target, it is desirable to shift the sight aiming point to account for the target range and the trajectory deviations due to crosswind. The art does not provide a satisfactory method and apparatus, particularly applicable to small-sized arms, for permitting the shooter to displace the side aiming point or method and apparatus for automatically displacing said side aiming point, according to target range and crosswind velocity.
Determination of the target range from a given base point, wherein the term "target" does not have a military significance, but can indicate any object the range of which it is desired to determine, by projecting onto the target a laser beam and measuring the time interval between the emission of the laser pulses and the reception of the corresponding echoes received at the base point, due to the reflection of the laser beam from the target, is known in the art. Determination of the crosswind intensity by means of laser beams has been recently proposed.
R. S. Lawrence et al, in Applied Optics, Vol. 11, No. 2, pp. 239-243, describes the use of laser scintillation patterns to measure average wind speed.
U.S. Pat. No. 5,123,730 describes an apparatus which comprises a light source, and a beam splitter for splitting a beam of light into a first transmitted beam segment, and a seconds low beam. A mechanism is provided for shifting the frequency of one or both beam segments and for directing the first beam segment to a target. A remote target for scattering the first beam is provided, said remote target being, for example, aerosol. A mechanism is provided for combining the scattered first beam segment returning from the target and the second beam segment into a combined beam and detecting the combined beam. A detector is operative to generate a sign indicative of crosswind along the path of the reactive first beam segment. A mechanism for determining wind speed normal to the path from the generated signal is also provided. Such a mechanism, while useful for meteorological determinations, cannot provide fire control.
Ting-1 Wang et al, in Applied Optics, Vol. 20, No. 23, pp. 4073 -4081, discusses various methods of correlation analysis usable to deduce crosswind from a drifting scintillation pattern, and conclude that no technique is ideal, but suggest to use a technique based on the cross-co variance function, of which they give a mathematical analysis.
U.S. Pat. No. 4,182,570 discloses a device for measuring a component of wind speed, which comprises a laser generator suitable for emitting a laser beam towards a target, two photo-electric receivers located transversely with respect to the initial axis of the laser generator to receive a part of the energy of said beam, and a circuit for processing the electrical signals delivered by the receivers to determine the slope of the origin of the normalized covalence function corresponding to said signals, the slope being representative of the component of the speed of wind blowing in the path of a laser beam in the direction of the straight line passing through the receivers, wherein the laser generator includes means for emitting said beam in successive groups of two pulses, the pairs of pulses being separated by a predetermined time interval, and wherein the receivers are so disposed in the proximity of the generator that each receives an echo of the laser pulses returned by the target. It is stated in said patent that the device can be applied to an artillery firing control system, but such an application is not described, nor are any instructions given for carrying it into practice.
J. Fred Holmes et al, in Applied Optics, Vol. 27, No. 12, pp. 2532-2538, describe the use of speckle-turbulence interaction to measure the vector wind in a plane perpendicular to a line of sight from a laser transmitter to a target.
It is an object of this invention to provide a firing control system (FCS) that is more accurate than any such system provided by the art.
It is another object of this invention to provide an FCS method and device that is applicable to all flat trajectory weapons, particularly to small arms.
It is a further purpose of this invention to provide a device for FCS which is of small size--"miniaturized"--and therefore applicable to portable weapons.
It is a still further purpose of this invention to provide a method and apparatus which permit the shooter of a weapon, particularly a small weapon, to adjust the weapon sight so to compensate for deviations due to crosswind along the intended projectile trajectory.
It is a still further purpose of this invention to provide a method and apparatus which permits automatically to displace the sight aiming point to compensate for crosswind and drop of the bullet along the trajectory.
Other purposes and advantages of this invention will appear as the description proceeds.